Die for forming carton blanks



July 25, 1961 H. 1... PHILLIPS ETAL DIE FOR FORMING CARTON BLANKS 4Sheets-Sheet 1 Filed Aug. 12. 1958 INVENTORS HARRY L. PH/LL/PS L) 77' ON5. FA/N m ww A 7'7'ORNEYS July 25, 1961 H. L. PHILLIPS ETAL DIE FORFORMING CARTON BLANKS Filed Aug. 12. 1958 4 Sheets-Sheet 2 LYTTON S.

23 |9 |7/' Q X N\\ I f a FIG... 6 4 I [3 1\ INVENTORS HARRY L. PHILLIPSFA/N ATTORNEYS y 1961 H. L. PHILLIPS ETAL 2,993,421

DIE FOR FORMING CARTON BLANKS Filed Aug 12, 1958 4 Sheets-Sheet 5 FIG. 7

13 INVENTORS HARRY L. PH/LL/PS LYTTON S. F4/N W MJW K A 7' TOPNEVS July25, 1961 H. L. PHILLIPS ETAL DIE FOR FORMING CARTON BLANKS 4Sheets-Sheet 4 Filed Aug. 12, 1958 FIG. /2

INVENTORS HARRY L. PH/LL/PS LYTTON 5. FA/N 757M] ATTORNEYS 2,993,421 DIEFOR FORMING CARTON BLANKS Harry L. Phillips, Piedmont, and Lytton S.Fain, San

Leandro, Califi, assignors, by direct and mesne assignments, to FlosealCorporation, Oakland, Calif., a corporation of Delaware Filed Aug. 12,1958, Ser. No. 754,632 3 Claims. (Cl. 93-58) This invention relates todie structure generally, and more specifically to dies for formingcarton blanks.

One of the objects of the invention is the provision of a die for use ona flat bed press, which die is adapted for forming carton blanks havingseparate spaced out and creased portions that must be in accurateregistration with each other when the blank is folded to form the cartonin order to produce the carton.

Heretofore the conventional practice has been to hold the cutting andcreasing rules in their desired positions for forming a carton blank(including intricate portions that must be in registration when theblank is folded to form the carton) by use of wooden blocks that are cutto the desired shapes by jig saws. The rules are prebent to form cuts orcreases and the blocks are positioned at opposite sides of the rules andhave the same surface contours as the rules held thereby.

This method and structure is very old, and is quite satisfactory wherethe problem of accurate registration between separate parts of theblanks that are formed by the dies is not involved. However, where, asin many present day cartons used for frozen foods and other products inwhich automatic machinery folds the blanks to carton form and wherecertain flaps and walls have relatively intricate interlocking tabs thatmust be in accurate registration with each other to properly form thecartons, the old die structure and method of making it, are notsatisfactory. No matter how carefully the wooden supporting blocks areformed and fitted in the die, they will not hold the relativelyintricately arranged rules rigid or fixed, in those portions of the diethat are to form the parts of the blank that later must be in accurateregistration with each other. The present day losses resulting fromrejected cartons formed by cutting and creasing rules that have shiftedrelative to each other, is enormous.

With the present invention, the production of a durable, light weightdie, and one in which the rules are frictionally held by the blocksseparating them so that individual rules may be replaced if nickel orworn without injury to the die and without requiring any accessorymechanisms.

Other objects and advantages will appear in the description and in thedrawings.

In the drawings:

FIG. 1 is a perspective view showing a conventional die in a frame asthe initial step in forming a mold for a die of this invention.

FIG. 2 is a reduced size top plan view of the die of FIG. 1, includingthe frame, supported by ordinary quoins in a conventional chase.

FIG. 3 is a cross sectional view taken along line 33 of FIG. 2.

FIG. 4 is an enlarged top plan view of the die of FIGS. 13 in the nextstep in the method, in which a block is on plastic in the mold andknock-out ejector pins and openings or bores are in the block.

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4 showingplastic material in the structure of FIG. 4 in the step of forming amold.

FIG. 6 is a view similar to that of FIG. 5 showing the plastic materialaround the block that is shown in FIG. 5.

rates atent O FIG. 7 shows the top block or mold that is formed by thestep illustrated in FIG. 6.

FIG. 8 is a top plan view of the mold of 'FIG. 7 in a frame preparatoryto forming a die.

FIG. 9 is a sectional view taken along line 9-9 of FIG. 8.

FIG. 10 is a sectional view similar to that of FIG. 9 but with theaddition of plastic for forming the die.

FIG. ll is a sectional view similar to that of FIG. 10 showing the nextstep in forming the die.

FIG. 12 shows the finished die in a frame with the rules therein.

In detail the initial step in making the mold for dies of the presentstructure comprises making a conventional die from steel rules 1 thathave been cut and formed to have the desired and necessary contours forcutting and creasing a car-ton blank. Wooden blocks 2 are cut to havecontours corresponding to that of the rules that are between the blocks,and certain rules 3 may, if desired, be supported at one of their sidesby one of the side members of the frame 4 that encloses the die and thatfunctions to hold the rules and blocks in their desired relationship toeach other.

The frame 4 differs from the ordinary frame in that its sides extend toa level above that of the upper edges of the rules and which edges arethe cutting and creasing or scoring edges. The distance to which suchside members may extend is preferably about three quarters of an inch.

In the die herein illustrated are two groups of rules 5, 6 (FIG. 2) thatare rather intricately arranged and close together, and which groups areadapted to form different portions of a carton blank that, ultimately,must coact with each other when the carton is formed. This coactionrequires very accurate registration between said portions, or partsthereof. Otherwise, the carton will be inoperative for accomplishing thedesired results, which results extend to the actual formation of thecarton itself.

' The members of frame 4, and the rules, are supported on a fiat base 7so that the cutting and creasing rules will be at the correct height forperforming their functions if the die were used on a flat bed press toform a carton, and if the side frame members were of less height thanthat of the rules. 'I-Iowever, base 7 supports the frame members so theyare higher at their upper edges than the upper edges of the rules, ashas been explained.

After the die is formed within frame 4, it is positioned within anordinary chase '8 on the base of the latter, and is locked] therein byuse of the usual blocks or shims 9 and quoins !10. The cutting andcreasing edges of rules 1, '3 are upwardly directed, the same as in FIG.1 and the rules, blocks 2, and frame 4 are all supported on the flatbase.

The next step in the method is to fill the spaces between the rules andthe space between the block and the frame, with an epoxy plastic 12 thatpreferably may be in the proportion of approximately 5 ounces of what isknown in the trade as Epoxy Resin G, which in itself may be an epoxymodified with a polyamide resin and a filler of metal powder, such asaluminum. To this is added approximately one ounce of an epoxy hardenerand then 10% by weight of a flexicizor, which is preferably a balancedthiocol base material. The hardener is well known in the trade as EpoxyL 930 A, and the flexicizor as Epoxy L 940.

The above materials are mixed together for approximately five minutestime and are then poured into the mold in a consistency that is similarto heavy syrup.

The frame 4, as seen in FIG. 2 is rectangular, and while the inventionis not necessarily restricted to a rectangular die or frame, such diesand frames are preferable 3 since they are readily locked in the usualchase 8 and are readily locked on the bed of a press.

After the level of the plastic is slightly higher than the upper edgesof the rules 1, 3, and said upper edges may vary slightly as between thecutting rules and the creasing rules, the latter being slightly belowthe upper level of the cutting rules, a rectangular block 13 ispositioned within frame 4 and on the plastic body 12.

This block 13 is preferably made of plywood and is formed around itsouter peripheral edge with an outwardly opening groove or channel 14.

Block 13 corresponds in shape and proportions (in plan view) to theframe 4, but is smaller by approximately a quarter of an inch on eachside, so that a space of ap proximately one-eighth of an inch, asindicated at 15 in FIG. 5, will be between each side of the block andthe side of the frame 4 opposed thereto, when the block is centeredwithin the frame.

The block 13 is formed with plurality of vertical open ended bores orpassageways 16 therethrough at right angles to the parallel flat upperand lower horizontal faces 17, 18 of the block and counter bores 19 areat the upper ends of each bore 16.

It is particularly pertinent to note that the lower ends of these bores16, for the most part, terminate close to rules 1 and at or closelyadjacent to intersecting points of rules in groups 5, 6, and several arepositioned within the large areas 20 in which there are no rules.

Other bores 21 similar to bores 16 extend through the block, but thesedo not have counterbores. Knock-out pins 23 are positioned within bores21, which pins have circular heads 24 that project below the lowersurface of the block 13.

The upper surfaces of the die blocks 2 and the upwardly projectingportions of rules 1, 3, including the inner surfaces of the frame 4 maybe suitably waxed to preclude the plastic sticking to them.

It should be noted that the bores 23 are positioned between adjacentpairs: of the relatively long central rules of the die, and are withineach group of rules 5, 6, with the heads 24 spaced from the rules.

The block 13 may now be forced downwardly by any suitable press 25 (FIG.6) until the block is stopped by its engagement with the uppermost edgesof cutting rules. Thus a relatively thin amount of the plastic may bebetween the creasing rules and the block.

This action in forcing block 13 downwardly results in the plasticmaterial rising around the outer peripheral sides of the block 13filling the grooves 14, and also in filling bores 16 and counterbores1-9. The heads 24 on the kock-out pins 23 will be surrounded by theplastic. The thickness of these heads may be substantially equal to theheight that the rules project from the lower die.

After the block 13 is in the position seen in FIG. 6' in which theplastic extends almost to the top level of the block in the space 15 andsubstantially fills the counterbores 19, the assembly, exclusive of thepress and chase, is preferably held at substantially room temperature of7277 for about twelve hours after which the plastic is sufficiently hardto enable removal of the block 13, with the plastic carried thereby,from the frame 4 and the rules 1, 3. The separation of the mold from thedie may be facilitated by tapping the exposed upper ends of theknock-out pins while lifting the block 13 by any suitable means that mayengage the exposed sides of the block adjacent to its upper surface.

The block 13 and the plastic are very tightly locked together as a unitby the plastic 27 that extends between. the outer sides of the block andframe 4, and that fills grooves 14, and by the plastic 28 in bores 16and 29 and in counterbores 1 9; and also the plastic in space 15 betweenblock 13 and the frame 4 provides an accurate peripheral outer surfaceof exactly the size of the frame so that the mold, which comprises theblock 13 and the plastic carried thereby as a unit therewith, will fitthe frame in precisely 4 the same manner as the die that is made up ofrules 1 and blocks 2, hence the mold may be substituted for said die inthe frame and will be of exactly the same size, in plan view, as thedie.

The plastic of the mold, above described, will progressively harden tothe point where it is, for practical purposes, substantiallyindestruct-able. The plastic does not shrink and the mold is very light,being substantially of wood. These molds may be made economically and anindefinite number of dies can be made therefrom.

The layer of plastic 28 that is between the rules 1, 3 and that is overthe areas 20 is, of course, exactly equal in thickness to the distancethe cutting rules project from the blocks 2 of the die, and the bases ofthe grooves 31 (FIG. 7) that are formed in the mold 26 COllLfOIIIl tothe cross sectional contours of the projecting portions of the rules.

The next step in forming a die from mold 26 is to position the mold in aframe 33 (FIG. 9) that may be identical with the frame 4, since the moldcontour will be identical with the die of FIGS. 1, 2. The frame may besupported on a base 34 that is similar to base 7. The grooves 31 openupwardly, hence block 13 is supported on base 34.

A conventional parting wax may be applied to the upper surface of themold and rules 36 are positioned in the recesses 31, said rules and thesides of the frame 33 being waxed to prevent plastic from adheringthereto. The rules are pre-formed to correspond to the rules 1, 3 exceptthat the longer rules 37 have aligned U-shaped recesses 38 formedtherein, which recesses open outwardly of the upper edges of the rulesas seen in FIG. 9, but which edges will ultimately be the lower edges ofthe rules, since the cutting and creasing edges are in the mold. Alsoalong the areas 39 (FIG. 8) that correspond to areas 20 in FIG. 4, thelong rules 40 that are perpendicular to rules 37 are formed withU-shaped recesses 41 of substantially greater depth than recesses 38,although the latter could be of the same depth as the recesses in rules40.

Within the aligned recesses 41 is a metal dowel 42, preferably ofaluminum, and metal dowels 43 are positioned in the aligned recesses 38(FIGS. 8, 9). When these dowels are so positioned, the uppermost dowels43 do not project above the upper level of the edges of the rules.

Following the positioning of the rules and dowels, as above described,plastic material 45 of the same kind as plastic 12, except with theaddition of ground walnut shells, is poured into frame 33 and betweenand around the rules to a level slightly above the level of the upperedges of the rules, as seen in FIG. 10. This material may be tamped toinsure against the entrapment of air.

One suitable formula for the plastic 45 is parts epoxy G resin, 15 partsepoxy hardener, 8% to 10% by weight of epoxy flexicizor, which is abalanced thiocol base material, and 25% to 30% by weight of groundwalnut shells. These ingredients are thoroughly mixed together and forma relatively thick but fiowable plastic mass.

The same formula as given for the mold plastic 12 may be used, exceptthat approximately 7 to 10 ounces of walnut shells is added.

This produces a strong die that is light in weight, and one in which thecast material does not affect the temper of the rules, nor does itshrink away from the rules.

After the plastic material 45 is poured as above mentioned, a centrallyapertured block 46 adapted to closely (but slidably) fit within frame 33is positioned over the plastic 45. This block carries a layer 47 ofuniform thickness of yieldable, rubber-like material, such aspolymerized chloroprene, known under the trade name of Neoprene.

The frame maybe locked in the chase in the same manner as described formaking the mold.

' The block 46 is forceably pressed downwardly by any suitable press 48until the upper edges of the rules are impressed into the layer 47.Surplus plastic will pass through the central opening 49 of the blockand layer 47 into a free space within the press 48 above the block.Since the rules may have small gaps where they intersect, the plasticbetween the various rules can readily find escape to the central opening49.

The above step insures against there being any plastic material on theupper edges of the rules, as seen in FIG. 11, and which upper edges willbe the bottom edges of the plastic die in which the rules are held.Also, the level of the plastic 45 between and at opposite sides of therules will usually be slightly lower than the plane in which said edgesare positioned. The distance that the edges of the rules sink into thelayer 47 is preferably approximately one sixty-fourth of an inch.

After approximately two hours at 7277 F. the plastic 45 is suflicientlyhardened that the die may be removed from the mold and frame 33. Theknock-out pins 23 facilitate such removal. The die may then stand atatmospheric temperature for approximately 8 hours at the end of whichtime it is completely hardened.

FIG. 12 shows the completed die in a frame 50 in which the die is readyfor use.

The starting temperatures of approximately 77 F. for the mold and thedie are preferably employed to start the development of the heat ofreaction that occurs.

In the mold, the layer of plastic is relatively thin, beingapproximately three-sixteenths of an inch thick, except for the lateralsides which are one-eighth of an inch in thickness, and the die isapproximately threequarters of an inch in thickness. This is pertinent,since the thickness is limited to approximately 1 /2 inches by the heatgenerated by the chemical hardener.

The positioning of the dowels 42, 43 may be somewhat arbitrary, but itis highly desirable and even essential to use them where there are largeareas in the die that are not crossed by rules. While the plasticmaterial will continue to harden with age, the die is removable from theframe 33 and is usable immediately after such removal without injury,but there is a tendency of the large ones to break, before they arefully hardened, unless they are reinforced by the dowels.

In the die, as above described, the individual rules are so firmly heldin place that the die can be handled as a unit with the rules remainingin place. However, the rules are only frictionally held, and may beseparately removed and replaced, which enables the user to replace anicked or worn rule instead of replacing the entire die.-

A plurality-of molds may be formed in one block, if desired, so that thedie produced therefrom may be a multiple die, such as a four-on oreight-on die, etc. Dies produced by the above process may be used asmaster dies for forming molds that, in turn, are identical with eachother, and may be used to make other dies.

In the carton making art the lack of uniformity in the wooden block typedies has been one of the most disturbing elements in the industry, sincethere could be no uniformity when the blocks used were formed by hand.

In the die, it will be seen that cast blocks take the place of thewooden blocks in the conventional die, except that the dowels in thepresent structure would prevent the blocks in which they are embeddedfrom being removed from the mold, and there is suflicient frictionalresistance between the blocks and the rules in the present die toprevent the blocks from being removed except by use of considerableforce. There is no occasion to remove the blocks, and the rulesthemselves are very seldom removed, except in case of an accident, whenone or more may be nicked. Hence, while the rules may be removed andreplaced, they fit so perfectly that a rawhide hammer usually must beused to tap a replacement rule in place, after which it normally staysin place by frictional resistance between it and the plastic blocks.

The formation of the mold as described is quite important. The lockingof the plastic to the block 13 as described produces a durable, lightweight mold that can be shipped and handled and used an indefinitenumber of times to produce dies that are absolutely uniform andidentical with the original die.

The particular die that is illustrated is merely by way of one example,it being obvious that many other molds and dies may be formed in thesame way.

We claim:

1. A die for forming a carton blank from a sheet of cardboardcomprising; a plurality of cutting and creasing rules disposed alonglines defining the outline of the blank to be cut from said sheet andthe creases to be formed in said blank along which said blank is to befolded to form a carton, said rules having coplanar base edges extendinglongitudinally thereof for direct engagement with the flat planar bed ofa press, the edges of said rules opposite to said base edges being thecutting and creasing edges of said rules, a hardened, plastic materialbetween said rules in cast, tight, frictional, but releasable engagementwith said cutting and creasing rules for supporting the latter rigidrelative to each other and perpendicular to such bed when said baseedges are supported thereon, rigid rods extending between and acrosscertain of said rules wholly imbedded within said plastic material,recesses opening outwardly of the base edges of the rules across whichsaid rods extend and within which said rods are positioned to enableremoval of said last mentioned rules from the side of said plasticmaterial opposite to said base edges.

2. A die for forming a carton blank from a sheet of cardboardcomprising; a plurality of cutting and creasing rules disposed alonglines defining the outline of the blank to be cut from said sheet andthe creases to be formed in said blank along which said blank is to befolded to form a carton, said rules having coplanar base edges extendinglongitudinally thereof for direct engagement with the flat planar bed ofa press, the edges of said rules opposite to said base edges being thecutting and creasing edges of said rules, a hardened, plastic materialbetween said rules in cast, tight, frictional, but releasable engagementwith said cutting and creasing rules for supporting the latter rigidrelative to each other and perpendicular to such bed when said baseedges are supported thereon, rigid rods extending between and acrosscertain of said rules wholly imbedded within said plastic material,recesses opening outwardly of the base edges of the rules across whichsaid rods extend and within which said dowel rods are positioned toenable removal of said last mentioned rules from the side of saidplastic material opposite to said base edges, the said rules acrosswhich said rods extend including a spaced opposed pair with the saidrods extending across the space between said pair and projectingoppositely outwardly of said pair whereby the plastic material at theopposite outer sides of said pair will be reinforced and held by saidpair against relative movement upon said removal of either of saidrules.

3. A die for forming a carton blank from a sheet of cardboardcomprising; a plurality of cutting and creasing rules disposed alonglines defining the cuts and creases to be formed in said sheet forforming the carton blank, said rules having coplanar base edges oppositeto said cutting and creasing edges extending longitudinally of saidrules for supporting them directly on the planar surface of a rigid bedduring the application of pressure against said cutting and creasingedges in a cutting and creasing operation; certain of said rules beingin spaced side by side relation and others of said rules being disposedalong lines extending transversely relative to said certain of saidrules; a body of hard, plastic material between and enclosing saidcertain of said rules and said others thereof in tight, cast,frictional, but releasable engagement with opposite sides thereofleaving their said base edges, cutting and creasing edges, andrelatively narrow marginal portions along said cutting and creasingedges, exposed; rigid rods respectively extending across said certain ofsaid rules and the areas therebetween and across said others of saidrules and across each other, enclosed within said body in tight holdingrelation to said body for holding the portions of said body between andat opposite sides of said certain of said rules, and said others of saidrules, stationary relative to each other when said rules are removed andupon compressive pres! sure being placed upon said body in the plane ofthe die when the die is locked in a chase, said certain of said rulesand said others of said rules being formed with recesses openingoutwardly of said base edges and References Cited in the file of thispatent UNITED STATES PATENTS 348,548 Crump Sept. 7, 1886 380,099 DuncanMar. 27, 1888 537,470 Mann Apr. 16, 1895 1,133,020 Goodwin Mar. 23, 19151,453,123 Bickett Apr. 24, 1923 1,776,622 Errington et al. Sept. 23,1930 1,935,942 Conner Nov. 21, 1933 2,460,242 Renaud Jan. 25, 19492,565,134 Kish Aug. 21, 1951 2,817,273 Phillips et a1. Dec. 24, 1957

